In pressurized foam dispensers of the above-mentioned type, a foamable concentrate, generally an aqueous soap solution, is contained in a dispenser equipped with a dispensing head and valve, and pressurized with a normally gaseous propellant, e.g., a low molecular weight hydrocarbon or hydrocarbon mixture or a halohydrocarbon or halohydrocarbon mixture. Upon discharge of the emulsion through the dispensing head the volatilization of the dispersed liquid droplets of propellant causes the dispensed concentrate to foam. Depending upon the precise formulation of the concentrate, the dispensed product may range from a dense creamy foam to a light foam.
The term "emulsion" will be used throughout this specification and claims to refer to the whole liquid contents of the dispenser, i.e., the foamable concentrate plus liquid phase propellant, and the term "concentrate" will be used to refer to the liquid contents of the dispenser, other than the propellant, "liquid" in this context embracing solutions, emulsions and suspensions. In other words, the concentrate itself may be an emulsion or suspension and not necessarily a solution of the foam producing ingredients in a suitable liquid medium, which, in the case of the present invention, will be water. The term "mousse", as used herein, is the same as foam, and refers to the dispensed product unless otherwise specified.
The cleaning of skin with surface-active cleaning preparations has become a focus of great interest. Many people wash and scrub their skin with various surface-active preparations several times a day. Ideal skin cleansers should cleanse the skin gently, causing little or no irritation without defatting and overdrying the skin or leaving it taut after frequent routine use. Most lathering soaps, liquids and bars included, fail in this respect.
Certain synthetic surfactants are particularly mild. However, a major drawback of most mild synthetic surfactant systems when formulated for skin cleansing is poor lather performance compared to the highest bar soap standards (bars which are rich in coconut soap and superfatted). On the other side, the use of known high sudsing anionic surfactants with lather boosters can yield acceptable lather volume. Unfortunately, however, the highest sudsing anionic surfactants are, in fact, poor in clinical skin mildness. Surfactants that are among the mildest, such as sodium lauryl glyceryl ether sulfonate, (AGS), are marginal in lather. These two facts make the surfactant selection, the lather and skin feel benefit formulation process a delicate balancing act.
Moisturizers provide skin conditioning benefits. E.g., it is known that glycerin is added to bars and liquid cleansing products for skin benefits. Glycerin in liquids at levels of greater than 8% is extremely difficult to lather and in nonsoap bars is difficult to process. Glycerin has also been used in a soap based shaving cream at a 10% level.
U.S. Pat. No. 3,959,160, Horsler et al., issued May 25, 1976, discloses aerosol shaving foam compositions which comprise soaps or nonsoap anionic surfactants and fatty alcohols. The Horsler et al. examples include up to 5% glycerin. This patent does not disclose higher levels of moisturizer or polymeric skin feel aids.
Examples of mild liquid cleansing compositions are disclosed in the following references. U.S. Pat. No. 4,338,211, Stiros, issued Jul. 6, 1982, discloses liquid skin cleanser with 2.3% to 3% AGS, the polymer JR400 and small amounts of free fatty acid plus a fatty acid alkylolamide as lather boosting agents. Compositions containing the surfactants AGS, betaine and sarcosinate are not disclosed.
U.S. Pat. No. 4,491,539, James J. Hoskins and Adriaan Kessler, issued Jan. 1, 1985, discloses liquid cleansing products comprising about 5% to 30% of surfactant, about 0.1% to about 1.0% of guar material, about 0.15% to about 1.0% of nonionic carboxyvinyl polymer, and water. Exemplary compositions containing the surfactants AGS, betaine and sarcosinate are not disclosed. British Pat. No. 2,103,236A, Colgate, Feb. 16, 1983, discloses a light duty, liquid detergent containing guar gum, a ternary surfactant mixture including betaine. AGS is not used. British Pat. No. 2,114,994A, L'Oreal, Sept. 1, 1983, discloses a cleansing product based on acylisethionates and cationic polymers, and is incorporated herein by reference.
Rather stringent requirements for skin cleansers limit the choice of surface-active agents, and final formulations represent some degree of compromise. Mildness is often obtained at the expense of effective cleansing, or lathering may be sacrificed for either mildness, product stability, or both.
None of the above-cited prior art formulations contain the composition of mild synthetic surfactant, high level of moisturizer with polymer skin feel aids.